After left guard Donald Thomas' season-ending quadriceps injury was confirmed Thursday, the reality of a woefully inexperienced interior offensive line could not be sugarcoated.

"Doesn't matter what position," Pagano said. "Anytime you have to play with young guys, particularly rookies, you are concerned."

With an interior line that likely will consist of first-time starter Khaled Holmes at center, second-year player Hugh Thornton at right guard and — replacing Thomas at left guard — rookie Jack Mewhort, the Colts will be light on experience at a position where it is invaluable.

Offensive line is among the most mentally-challenging positions in the game, with defenses constantly scheming to fool blockers and create pressure on quarterbacks. The root of the Colts' constant offensive line issues in 2013 was the performance of interior linemen.

Just ask quarterback Andrew Luck, who had to contend with an unrelenting interior pass rush last season.

Pagano, despite his candor, suggested things might not be as bad as they appear. He's seen rookies and other young players elevate their play before.

"We saw in (2012), Dwayne Allen as a rookie, Coby Fleener as a rookie, T.Y. Hilton as a rookie, Vick Ballard as rookie — just to name a few — come in and play damn good football and play at a high level," Pagano said. "These guys will rise to the challenge and they'll play and play well."

Mewhort takes center stage with Thomas' injury. Had Thomas remained in the lineup, Mewhort was likely to be the top reserve on the offensive line, a luxury considering his ability to play all five positions.

Now, Mewhort is likely to be pressed into action at left guard. The second-round choice from Ohio State looks the part at a chiseled 6-6 and 308 pounds.

But there are some less-obvious qualities that bode well for his success, too. Mewhort is a cerebral player, one of the characteristics that drew the Colts to him in the NFL draft.

"The game is so much faster (than college)," Pagano said. "... Things happen a little bit faster, scheme-wise, (pro teams) do a little bit more especially on third down so it certainly helps to have guys that have great understanding of concepts and pick up our scheme, number one. He is a guy that is going to spend the amount of time that he needs to spend in the film room studying and getting everything down and getting on the same page. We have a bunch of bright guys across the board. It helps to have a guy under center (Holmes) that's pretty damn smart, too."

Said Mewhort: "The whole game just speeds up. I don't know if it particularly has to do with changing up positions as much as just transitioning to the NFL. Everything clicks so much faster, and with a quarterback like Andrew (Luck) things are moving fast out there so you always have to have your mind ready to go."

Keep in mind, this is only practice. The game gets faster once games start being played.

But Mewhort has the ability to be a solid pro. His versatility suggests he's not only smart but a good athlete. He also showed considerable toughness at Ohio State, something the Colts hope translates.

But projections are just that. Where Mewhort, Holmes and Thornton are concerned, so much still must be proven.

This much we know now: The Colts are putting it all on the line — literally.